The present invention relates in general to flashlights and the electrical circuitry and connections therefor, and is more particularly directed to a miniature pocket flashlight having a flexible exterior case which, when squeezed, depresses an internal switch to complete the circuit and illuminate a lamp.
Various styles of miniature flashlights have enjoyed considerable commercial success due to their compactness, utility and reliability. Certain types of known flashlights employ soldered, welded or riveted connections. Exemplary of these are U.S. Pat. Nos. 4,429,352; 4,122,510; 3,796,869; and 3,330,949. The present inventor has had U.S. Pat. No. 4,419,718 issued to him which discloses the use of a switch wire, tightly coiled around the positive terminal of one battery, and a lead wire for the lamp wound about the positive terminal of a second battery. On the other hand, U.S. Pat. Nos. 4,443,833 and 4,032,773, provide solderless connections which rely upon certain crimping techniques and the aid of a flexible cover end cap retaining a metallic switch element against the terminal of a battery.
Usually, these miniature flashlights are designed for keeping in a purse, pocket or briefcase. They have generally been made disposable whereby the batteries cannot be replaced once exhausted due to their encasement in a sealed flexible covering member.
Of critical importance to the reliability of such flashlights is the prevention of the inadvertent activation of the switch, such as when the flashlight is placed in a purse and comes into contact with other surrounding items. Additionally, the prevention of shorting between the negative and positive terminals caused by excessive bending of the switch means arranged near one of the batteries is important to the longevity of the flashlight. The device disclosed in U.S. pat. No. 4,419,718 alleviates, to a large extent, the inadvertent electrification of the lamp, as well as avoiding the short circuit problem with the battery to which the switch means is in contact with the positive terminal thereof, by means of a unique fulcrum-like design for the switch means. The present invention is a combination with, and an improvement upon, certain features of the aforementioned patent in a unique flashlight assembly.
The reliability of miniature flashlights is very important since, for example, they may be called upon to operate when a person is hurriedly searching for his or her house keys in an attempt to unlock an outside door during the evening hours. Manufacturing costs must also be kept to a minimum to maintain competitive advantage. The flashlights disclosed in several of the noted patents require solder connections for electrically joining the batteries and switch to the lamp. In addition to the potential problems with poor solder connections, the soldering processes require additional equipment and labor. A primary goal of the invention is to provide a flashlight having a resilient cartridge-type holder for the accommodation of a pair of batteries, a lamp, and electrical circuitry for the illumination of the lamp capable of being switch activated by means of squeezing a flexible case containing the cartridge, wherein the electrical connections are obtained by a compressive holding action of the cartridge involving no soldered connections.
A further goal of the invention is to provide a miniature flashlight that incorporates a squeeze-activated switch arm that bends only along a limited portion thereof whereby to avoid inadvertent electrification of the lamp and also the prevention of a short circuit between the terminals of one of the batteries.
It is a further goal of the invention to provide for a flexible switch arm that is arranged with a cartridge in such manner as to chafe against the positive terminal of the battery to which it is connected, whereby to clean the connection and eliminate corrosive buildup.
It is yet another object of the invention to provide a flashlight cartridge that securely spaces two batteries one from the other, which is capable of use with batteries having either insulated-type casings or uninsulated casings, whereby the miniature flashlight has the capability of receiving replacement batteries, or may be made to be disposable.
A concomitant goal of the invention is to also provide a cartridge-holder for a miniature flashlight capable of use with a switch arm that includes a fulcrum bend to allow only a limited portion of the switch arm to be bent, and/or wherein the cartriidge provides a central median pivot point intermediate the batteries whereby the switch arm abuts and pivots against the median to achieve the limited bending objective while being bent to complete the electrical circuit.
It is a further objective to provide a cartridge having opposing end walls capable of a wedging-engagement with batteries and wherein lead wires from the lamp are held by a compressive force once the batteries are resiliently inserted in the proper position.
It is additionally a goal to provide a conductor strip that is engageable with the cartridge and negative terminal of battery which is arranged to be contacted by the switch arm whereby insulated batteries may be utilized, or alternatively the uninsulated variety can be substituted therefor.
In summary, the miniature flashlight of the present invention employs a flexible outer case which contains a cartridge for holding a pair of batteries and electrical circuitry for the illumination of a lamp. The cartridge is provided with a twin cradle-portion for retention of the batteries and having, at opposite ends thereof, a pair of opposing resilient end walls capable of clamping lamp lead wires against the terminals of the batteries and retaining a switch arm arranged to complete the circuit and thereby illuminate the lamp when the user squeezes the flexible outer casing against the switch arm. One end wall supports the lamp and provides slit means for the receipt therethrough of the lamp lead wires to be fed onto raised interior portions of the end wall against which the batteries are held in compression. The switch arm is preferably double-bent near the middle whereby to provide an integral fulcrum to minimize the bending portion of the switch arm in alleviation of both the short circuiting and inadvertent electrification problems found in the prior art. A divider median portion of the cartridge separates the battery cradles and is cooperatively aligned with the switch arm to act as an optional pivot point for the arm to thereby reduce the bending length of the switch arm and thus require a relatively firm squeeze to depress it in order to prevent inadvertent activation of the electrical circuitry when the flashlight is stored in a purse, pocket, briefcase, or the like.
The end wall opposite the wall that supports the lamp includes means for receiving a portion of the switch arm below the positive terminal of one of the batteries whereby the battery terminal compressively contacts with the switch arm and wherein the switch arm, during squeezing and releasing of the flexible case, moves against the positive terminal to thereby abrade the terminal, keeping it clean from corrosion and build-up.
The cartridge is formed to accommodate either insulated or uninsulated batteries. The compressive action of the resilient end walls that hold the batteries allows for the utilization of a conductor strip to be arranged with the negative terminal of an insulated battery and extend along the battery to be disposed in the bending path of the switch arm, so that the switch arm may contact the conductor strip when depressed. The conductor strip may be eliminated when uninsulated battery casings are provided since the switch arm then simply contacts the exterior, or negative, metal casing of the battery to complete the circuit.
A cap is either removably or fixedly arranged with the flexible casing and provides an opening for the lamp to extend therethrough. In the fixed arrangement, upon the exhaustion of the batteries, the flashlight may be discarded. Alternately, a removable cap may be snap-engaged with the flexible casing whereby upon the exhaustion of the batteries, the cap may be removed and the cartridge and electrical circuitry removed as a unit in order to replace the batteries. In the latter form of the invention, the lamp may also be replaced when it has burned out.
The invention is largely characterized by the solderless connections made possible by the resiliently biased assemblage of the batteries and cartridge to secure the electrical connections therebetween.
The foregoing advantages are made possible by a cartridge which, in one embodiment of the invention, has, in cross section, a rounded W-shape configuration providing two parallel cradles opening outwardly in the same direction for retention of batteries in side-by-side relationship between top and bottom opposing end walls flexibly formed at opposite ends of the cradles. Along the peak of the W, a median strip is formed which may include a raised portion to act as a fulcrum for the pivoting of a spring arm compressively held at its lower end between a pair of upstanding ribs located on the bottom end wall of the cartridge to receive the positive terminal of one battery. The switch arm may be straight or may include a bent central portion which also acts as a fulcrum to limit bending to a limited portion of the switch arm. The switch arm is adapted to pivot and complete contact with the negative terminal of the second battery when the flexible case is squeezed. Additionally, a second battery experiences a compressive force when inserted in the other cradle against a raised portion of the opposite upper end wall to secure one of the lamp lead wires. The bottom of the first battery abuts against another raised portion on the upper end wall, whereby to compress the other lamp lead wire thereagainst, and is also wedged against another raised portion on the bottom end wall. Thereby both batteries experience a compressive force caused by flexing of the end walls upon insertion of the batteries into the cradles.
In another embodiment of the invention, the cartridge has an S-shape in cross section wherein the cradles open in opposite directions and the batteries are thereby separated by a reverse curve central portion. A portion of the reverse curve central portion may be used as an optional fulcrum point for either a straight or bent switch arm when depressed. The opposite end walls may include raised areas and ribs for the retention of the positive terminal ends and the bottom ends of the batteries similar to the first mentioned embodiment. In both embodiments, the batteries may be of either the insulated or the uninsulated variety. For the insulated variety, a conductor strip extends from the bottom negative terminal of one of the batteries upwardly into the path of the depressed spring arm whereby to facilitate completion of the circuit upon flexure of the outer casing.
The spring arms for either of the two disclosed embodiments may be substantially the same and include similar bent fulcrum portions for minimizing the bending of the switch arm. In all cases, the arrangement of the portion of the switch arm at the positive terminal of one of the batteries is provided to have a slight movement, whereby to chafe against the positive terminal to create a cleaning action.
Other advantages and features of the invention will become apparent from the detailed description hereinafter taken in conjunction with the drawings.